Multifactorial regulation of daily rhythms in expression of the metabolically responsive gene spot14 in the mouse liver.

Spot14 is a putative transcriptional regulator for genes involved in fatty acid synthesis. The Spot14 gene is activated in response to lipogenic stimuli such as dietary carbohydrate and is also under circadian regulation. The authors investigated factors responsible for daily oscillation of Spot14 expression.

Dehydroepiandrosterone upregulates soluble guanylate cyclase and inhibits hypoxic pulmonary hypertension.

Objective: It has been reported that dehydroepiandrosterone is a pulmonary vasodilator and inhibits chronic hypoxia-induced pulmonary hypertension. Additionally, dehydroepiandrosterone has been shown to improve systemic vascular endothelial function. Thus, we hypothesized that chronic treatment with dehydroepiandrosterone would attenuate hypoxic pulmonary hypertension by enhancing pulmonary artery endothelial function.

An mRNA amplification procedure with directional cDNA cloning and strand-specific cRNA synthesis for comprehensive gene expression analysis.

We developed an integrated system suitable for comprehensive gene expression studies including construction and analysis of cDNA microarrays starting from a small amount of mRNA. We amplified total mRNA first as cDNA mixtures by polymerase chain reaction and then as strand-specific cRNA mixtures by in vitro transcription. These amplified cDNA and cRNA enabled determination of mRNA levels by hybridization analyses such as Southern, Northern, reverse-Northern macroarray, and cDNA microarray analyses, as well as construction of the cDNA library with a unidirectional cDNA insert.

Two-peaked synchronization in day/night expression rhythms of the fibrinogen gene cluster in the mouse liver.

Genes expressed with day/night rhythms in the mouse liver were searched for by microarray analysis using an in-house array harboring mouse liver cDNAs. The rhythmic expression with a single peak and trough level was confirmed by RNA blot analysis for 3beta-Hsd and Gabarapl1 genes exhibiting a peak in the light phase and Spot14, Hspa8, Hspa5, and Hsp84-1 genes showing a peak in the dark phase. On the other hand, mRNA levels for all of the three fibrinogen subunits, Aalpha, Bbeta and gamma, exhibited two peaks each in the light and dark phases in a synchronized manner.